A new chemical synthesis method produces salvinorin analogs that are more potent, selective, stable, and functionally biased than the natural compound salvinorin A. These analogs target the kappa-opioid receptor and could serve as templates for next-generation pain relievers, anti-itch treatments, and dissociative hallucinogens. The synthesis uses a special organocatalyst and a cobalt-catalyzed cycloaddition to efficiently create a library of these complex molecules, overcoming previous difficulties in modifying their structure.
The authors report an optimized, scalable synthetic route for salvinorin-based probes that target the kappa-opioid receptor. Methodological improvements include substituting a Grignard reagent with an organozinc protocol and enhancing a samarium-mediated reaction with LiBr. These advances enabled the synthesis of two active positive-control probes and three negative-control probes. A screen of over 300 GPCRs confirmed the exceptional KOR selectivity of a novel alkyne probe, establishing it as a tool for validating target-specific engagement in situ.
Salvinorins are natural compounds that serve as templates for new analgesics, antipruritics, and dissociative hallucinogens by selectively activating the kappa-opioid receptor. Unlike most opioids, they lack basic amines and have complex structures that have hindered chemical modification. This work describes a short asymmetric synthesis using a sterically confined organocatalyst to enable a Robinson annulation of an unactivated nucleophile and unstable electrophile. Combined with a cobalt-catalyzed cycloaddition, the route provides access to a library of salvinorin analogs. The authors appraise the synthesis by generating multiple analogs that exceed the potency, selectivity, stability, and functional bias of salvinorin A itself.